1. Field of the Invention
The present invention relates to a plasma display panel for displaying an image.
2. Description of the Related Art
Generally, a plasma display panel (PDP) is a display device which excites phosphors with vacuum ultraviolet (VUV) rays radiated from plasma obtained through gas discharging, and displays desired images by using visible light of red R, green G, and blue B colors generated by the excited phosphors. The PDP has been in the spotlight as a flat panel display for TV and industrial purposes with several advantages. The PDP can realize a very large screen size of 60″ (˜152.4 cm) or more with a thickness of 10 cm or less, and involves excellent color representation, without image distortion due to viewing angles, since it is a self emissive display, like a cathode ray tube (CRT). The PDP further involves high productivity and low production cost as it is made in a more simplified manner compared to an LCD.
An alternating current type PDP (“AC PDP”) includes a rear substrate and a front substrate. Address electrodes are formed on the rear substrate and covered by a dielectric layer. Between the address electrodes, barrier ribs are disposed in a striped arrangement on the dielectric layer. A phosphor layer for generating visible light of red R, green G, or blue B color is formed between the barrier ribs. Display electrodes are formed on the front substrate facing the rear substrate. The display electrodes are arranged in pairs, and each display electrode includes a transparent electrode and a bus electrode. The display electrodes extend in a direction crossing the address electrodes. A dielectric layer and an MgO protective layer are consecutively formed on the front substrate, covering the display electrodes. A discharge cell is formed at each area where the address electrodes on the rear substrate cross a pair of display electrodes on the front substrate. Millions of discharge cells are arranged in the PDP in a matrix format. The discharge cells of an AC PDP arranged in a matrix format are driven by utilizing memory characteristics.
In more detail, in order to generate a discharge between X and Y electrodes that form a pair of display electrodes, a potential difference therebetween is required to be more than a specific voltage, which is called a discharge firing voltage Vf. In this case, a scan pulse and an address pulse Va of a discharge cell are respectively applied to the Y electrode and the address electrode, an address discharge is generated between the two electrodes, and thus the discharge cell is selected. Plasma is formed in such a selected discharge cell, and electrons and positive ions therein shift toward the electrode of opposite polarity.
Since the electrodes of the AC PDP are covered with dielectric layers, most of the shifted space charges (i.e., the above-mentioned electrons and ions) are accumulated thereon. Accordingly, the net space potential between the Y electrode and the address electrode becomes smaller than the originally applied address voltage Va so that the discharge becomes weak and finally vanishes.
In this case, a relatively small amount of electrons is accumulated on the X electrode, and a relatively large amount of ions is accumulated on the Y electrode. The charges accumulated on the dielectric layer covering the X and Y electrodes are called wall charges Qw, and the space voltage formed between the X and Y electrodes due to the wall charges is called a wall voltage Vw.
When a predetermined voltage (called a sustain voltage Vs) is subsequently applied between the X and Y electrodes, a discharge is generated in the discharge cell to produce VUV rays, in the case that the sum Vs+Vw of the sustain voltage Vs and the wall voltage Vw is higher than the discharge firing voltage Vf. The VUV rays excite the relevant phosphors, and visible rays produced thereby are emitted through the transparent front substrate
However, for a discharge cell that has not experienced such an address discharge between the Y electrode and the address electrode (i.e., a discharge cell to which the address voltage Va is not applied), wall charges are not accumulated on the X and Y electrodes, and consequently the wall voltage is not formed between the X and Y electrodes. In this case, only the sustain voltage Vs applied to the X and Y electrodes acts in the discharge cell. As the sustain voltage Vs is lower than the discharge firing voltage Vf, no discharge is caused in the gas space between the X and Y electrodes.
Terminals of the X and Y electrodes of the display electrodes are located at opposite sides of the PDP between the front and rear substrates. The terminals of the X electrodes are connected to a driving board (typically called an X board) for driving the X electrodes, through a flexible printed circuit (FPC). The terminals of the Y electrodes are connected to another driving board (typically called a Y board) disposed opposite to the X-board. The X and Y boards may be fabricated in the form of a printed circuit board assembly (PBA). Therefore, a path for applying the sustain voltage to the X and Y electrodes is elongated, and accordingly electromagnetic interference (EMI) is increased during the operation of the PDP. In addition, such a PDP requires separate X and Y boards, and accordingly driving circuits become complex.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the background of the invention, and therefore, unless explicitly described to the contrary, it should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art that is already known in this country to a person of ordinary skill in the art.